Hazmat, you might check with any van conversion company in your area. They usually have a bunch of brand new seats that have been replaced in the conversion process and they can be modified to fit your needs. The big flea markets/old car shows here on the ECoast have great selections and deals on PU seats; bet you have the same in your area. Also, bucket seats were options and the salvage yards quite often have some good stuff that will work. You can do some home work to see what years will interchange. I'm sure your cab is drilled and tapped to where you can blolt and unbolt. You may want to examine the carpet coverage under your bench and compare to bucket seat model to see if you need to be looking for carpet also.
Trees